Lead assembly including a polymer interconnect and methods related thereto

ABSTRACT

A lead assembly includes a ring component having mechanical coupling features, and at least one polymer component mechanically coupled with the mechanical coupling features of the ring component. Elongate tubing is disposed over the polymer component and is secured with the polymer component.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/006,156, filed on Jan. 13, 2011, which is a continuation of U.S.patent application Ser. No. 11/468,996, filed on Aug. 31, 2006, now U.S.Pat. No. 7,917,229, which are hereby incorporated herein by reference intheir entirety for all purposes.

Additionally, this application is related to U.S. patent applicationSer. No. 11/462,479, filed on Aug. 4, 2006, now published as U.S.Publication No. 2008/0046059, entitled “Lead Including A Heat Fused orFormed Lead Body,” assigned to a common assignee, and is herebyincorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

Leads for linking medical devices with selected bodily tissue to besensed or stimulated by such devices. More particularly, but not by wayof limitation, this relates to a lead including a polymer interconnectand methods related thereto.

BACKGROUND

Leads represent the electrical link between an implantable medicaldevice (referred to as “IMD”), such as a pacer or defibrillator, and asubject's cardiac or other bodily tissue, which is to be sensed orstimulated. A lead generally includes a lead body that contains one ormore electrical conductors extending from a proximal end portion of thelead to an intermediate or distal end portion of the lead. The lead bodyincludes insulating material for covering and electrically insulatingthe electrical conductors. The proximal end of the lead further includesan electrical connector assembly couplable with the IMD, while theintermediate or distal end portions of the lead include one or moreelectrodes that may be placed within or near a desired sensing orstimulation site within the body of the subject.

Implantable leads, such as those used for cardiac sensing orstimulation, should have the ability to remain fully assembled and leakresistant despite constant flexing or bending, which may be encounteredwith each ventricular or atrial contraction of cardiac tissue (withinwhich the lead is implanted or near) or axial forces applied to the leadduring implantation, repositioning, or lead extraction. In addition,implantable leads should be designed to resist failure due to extendedcontact with in vivo bodily fluids, such as blood.

What is needed is a lead having interconnects able to withstand axialforces disposed to the lead. What is further needed is a lead havinginterconnects that are capable of being manufactured without the use ofadhesive.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals describe substantially similar componentsthroughout the several views. The drawings illustrate generally, by wayof example, but not by way of limitation, the various embodimentsdiscussed herein.

FIG. 1 is a schematic view illustrating an implantable lead system andan environment in which the lead system may be used, as constructed inaccordance with at least one embodiment.

FIG. 2A is a cross-sectional view of a portion of a lead as constructedin accordance with at least one embodiment.

FIG. 2B is a cross-sectional view of a portion of a lead as constructedin accordance with at least one embodiment.

FIG. 2C is a cross-sectional view of a portion of a lead as constructedin accordance with at least one embodiment.

FIG. 3 is a side view of a portion of a lead as constructed inaccordance with at least one embodiment.

FIG. 4 is a side view of a portion of a lead as constructed inaccordance with at least one embodiment.

FIG. 5 is a side view of a portion of a lead as constructed inaccordance with at least one embodiment.

FIG. 6 is a side view of a portion of a lead as constructed inaccordance with at least one embodiment.

FIG. 7 is a side view of a portion of a lead as constructed inaccordance with at least one embodiment.

FIG. 8 is a side view of a portion of a lead as constructed inaccordance with at least one embodiment.

FIG. 9 is a cross-sectional view of a distal portion of the lead asconstructed in accordance with at least one embodiment.

FIG. 10 is a cross-sectional view of a distal portion of the lead asconstructed in accordance with at least one embodiment.

FIG. 11 is a cross-sectional view of a distal portion of the lead asconstructed in accordance with at least one embodiment.

FIG. 12 is a flow chart for a method as constructed in accordance withat least one embodiment.

FIG. 13 is a cross-sectional view of a distal portion of the lead asconstructed in accordance with at least one embodiment.

FIG. 14 is a cross-sectional view of a distal portion of the lead asconstructed in accordance with at least one embodiment.

FIG. 15 is a cross-sectional view of a distal portion of the lead asconstructed in accordance with at least one embodiment.

FIG. 16 is a cross-sectional view of a distal portion of the lead asconstructed in accordance with at least one embodiment.

FIG. 17 is a perspective view of a polymer component as constructed inaccordance with at least one embodiment.

FIG. 18 is a side view of a polymer component as constructed inaccordance with at least one embodiment.

FIG. 19 is a side view of a polymer component as constructed inaccordance with at least one embodiment.

DETAILED DESCRIPTION

The following detailed description includes references to theaccompanying drawings, which form a part of the detailed description.The drawings show, by way of illustration, specific embodiments in whichthe present leads and methods may be practiced. These embodiments, whichare also referred to herein as “examples,” are described in enoughdetail to enable those skilled in the art to practice the present leadsand methods. The embodiments may be combined, other embodiments may beutilized or structural and logical changes may be made without departingfrom the scope of the present leads and methods. It is also to beunderstood that the various embodiments of the present leads andmethods, although different, are not necessarily mutually exclusive. Forexample, a particular feature, structure or characteristic described inone embodiment may be included within other embodiments. The followingdetailed description is, therefore, not to be taken in a limiting senseand the scope of the present leads and methods are defined by theappended claims and their legal equivalents.

FIG. 1 illustrates a lead system 100 and an environment 106 (e.g., asubcutaneous pocket made in the wall of a subject's chest, abdomen, orelsewhere) in which the lead system 100 may be used. In varyingexamples, the lead system 100 may be used for delivering or receivingelectrical pulses or signals to stimulate or sense a heart 108 of apatient. As shown in FIG. 1, the lead system 100 includes an IMD(implantable medical device) 102 and an implantable lead 104. The IMD102 generically represents, but is not limited to, cardiac functionmanagement (referred to as “CFM”) systems such as pacers,cardioverters/defibrillators, pacers/defibrillators, biventricular orother multi-site resynchronization or coordination devices such ascardiac resynchronization therapy (referred to as “CRT”) devices,sensing instruments, or drug delivery systems.

Among other things, the IMD 102 includes a source of power as well as anelectronic circuitry portion. In one example, the electronic circuitryincludes microprocessors to provide processing, evaluation, and todetermine and deliver electrical shocks or pulses of different energylevels and timing for ventricular defibrillation, cardioversion, orpacing of heart 108 in response to sensed cardiac arrhythmia includingfibrillation, tachycardia, or bradycardia. In another example, the IMD102 is a battery-powered device that senses intrinsic signals of theheart 108 and generates a series of timed electrical discharges.

The lead 104 includes a lead body 202 (FIG. 2A) extending from a leadproximal end portion 204, where it is couplable with the IMD 102. Thelead 104 extends to a lead distal end portion 206, which is positionedwithin, on, or near tissue to be stimulated, such as a heart 108. Thelead 104 further includes at least one electrode 116 (FIG. 2A) thatelectrically links the lead 104 with the heart 108.

At least one conductor 120 (FIG. 2A) is disposed within the lead body202 and electrically couples the at least one electrode 116 with aterminal end of the lead 104 at the lead proximal end portion 204 andthe IMD 102.

FIG. 2A illustrates an example of a distal portion of the lead 104 ingreater detail. The lead 104 includes at least one polymer component 130that is mechanically coupled with a ring component 150, and allows for alead interconnection without the requirement of adhesive, although it ispossible to use the interconnect with an adhesive. The ring component150 includes, but is not limited to, a generally cylindrical ringcomponent. It should be noted more than one polymer component 130 can beprovided for additional joint integrity (see FIGS. 2C and 11). Anoptional drug eluting steroid collar 129 is provided adjacent to thering component 150.

The polymer component 130 includes a polymer ring, such as a ring formedof a thermoplastic, such as polyurethane, in an example. The polymercomponent 130 includes features that allow for the polymer component 130to be mechanically coupled with the ring component 150 at an interface132 (FIG. 3). For example, the polymer component 130 can be coupled withthe ring component 150 with a snap fit coupling or an interference fit.In another option, the polymer component 130 is overmolded on to thering component 150. In another option, the polymer component 130 isco-extruded, or coated on to the ring component 150, or coated on totubing and placed on the ring component 150. In another option, thepolymer component 130 is heat shrunk within a groove of the ringcomponent. In yet another option, the polymer component 130 includesanti-torque features, such as, assisting in preventing movement of thepolymer component 130 relative to the ring component 150. Optionally,the polymer component 130 has a lower melting point than the ringcomponent 150.

The polymer component 130 is disposed over the ring component 150. Thering component 150, in an option, is a metal component, for example,allowing for the ring component 150 to be used as a distal electrode 152of the lead 104. In another option, the ring component 150 is formed inwhole or in part of a higher melting point polymer (e.g. PEEK). In anoption, the ring component 150 includes at least one recess 154, such asan annular recess, allowing for the polymer component to be receivedtherein. Optionally, an inner metal tube 190 is disposed within the ringcomponent 150, as shown in FIG. 2B. The optional inner metal tube 190allows for the capture of, for example, coil filars and/or to size thelead lumen to allow a stylet to push the lead tip, and still allowguidewire passage. In another option as shown in FIG. 2C, at least onehole 155 is provided within the ring component 150, and optionally twopolymer components are sandwiched around the at least one hole 155. Whenfused together, as discussed further below, the polymer components flowtogether through the hole 155. An optional mandrel 157 provides supportfor the inner polymer component.

FIGS. 3-8 illustrate additional options for the ring component 150, suchas anti-torque features. For example, FIG. 3 illustrates a ringcomponent 150 having a textured, substantially non-smooth surface at theinterface 132, such as a knurled surface or a surface havingcross-threads thereon. FIG. 4 illustrates another option for the ringcomponent 150, where the ring component 150 includes a roughened surface158. The textured surface can be formed by grit blasting or machining,for example. Additional options for providing non-smooth surfaces areillustrated in FIGS. 7 and 8. For example, the ring component 150includes one or more holes 170 formed within the recess, as shown inFIG. 7, or one or more slots 172 formed within the recess, as shown inFIG. 8.

The ring component 150 includes mechanical coupling and/or anti-torquefeatures, such as the recess 154, allowing for the polymer component 130to be coupled therewith. FIGS. 5 and 6 illustrate additional options inwhich the recess 154 has a varying width 162. For instance, in FIG. 5,the width varies around the perimeter of the ring component 150. FIG. 6illustrates another option wherein the recess 154 includes one or moreteeth 164. The one or more teeth 164 allow for the polymer component 130to deform within the teeth 164, providing for additional strength forthe interconnection. The teeth 164 allow for the width of the recess 154to be varied around at least a portion of the perimeter of the ringcomponent 150. The teeth 164 can have a variety of shapes such as, butnot limited to, square, rectangular, triangular, circular, etc. Theseabove-discussed features are formed on the ring component 150, forexample, by machining the features thereon or therein.

Referring again to FIG. 2A, the polymer component 130 is mechanicallycoupled with the ring component 150, for example with ring componentcoupling features. Elongate tubing, such as the lead body, is disposedover the polymer component 130 and is coupled or secured therewith, forexample by fusing. Suitable methods for fusing the polymer component 130and the lead body 202 include, but are not limited to, applying energyto change the polymer component 130 including heat shrinking with heatand/or pressure, laser, inductive heat, or radio frequency, heat mandrelinside of joint, heated jaws, laser, or combinations thereof. Thisallows for a secure joint 180 (FIG. 2B) to be formed between the leadbody 202 and the polymer component 130 without the need for adhesive.

For additional sealing properties, an optional seal(s) 182 can beprovided between the polymer component 130 and the ring component 150,as illustrated in FIGS. 9-11. For example, an O-ring 184 can be providedwithin recesses 186 of the ring component 150. In another example, anelastomer, such as an elastomer with a ribbed shape 188, can be providedwithin the recess 186, where the elastomer forms a seal between the ringcomponent 150 and the polymer component 130. In another example, asshown in FIGS. 9 and 11, a joint 180 can be formed on one side of theseal 182, or on either side of the seal 182, providing for additionalsealing integrity. In yet another option, an outer band 181, such as ametal band or polymer band, such as a band resistant to creep, isprovided around the seal 182. In another option, an outer band 183, suchas a metal band or polymer band, such as a band resistant to creep, isprovided around the joint 180. The outer bands 181, 183 do not creepsignificantly, and assist with sealing integrity and increase axialjoint strength. The outer bands 181, 183 can be swaged into place usinga marker band swager or a rotary swager, for example, or welded orbonded in place.

Referring to FIG. 12, to form the lead assembly, at 210, a polymercomponent 130 is disposed over the ring component 150, where the ringcomponent 150 optionally includes mechanical coupling features, and at212 the polymer component 130 is coupled with the ring component 150. Inan example, the polymer component 130 is formed of polyurethane, and inan option having a durometer of 80A-80D. However, it should be notedthat the polymer component 130 is not necessarily so limited.

In an example illustrated in FIG. 13, the polymer component 130 is slidover the ring component 150, optionally over a ramp. In an option, thepolymer component 130 is slid into the recess 154. In an option, thepolymer component 130 is slid over the ring component 150 and into aninterference fit with the ring component 150. In a further option, thering component 150 and recess 154, and/or the polymer component 130 aresized such that the polymer component 130 fits in the recess 154 with asnap fit coupling, as shown in FIG. 14. In yet another option, thepolymer component 130 is slid longitudinally or radially over the ringcomponent 150 and is optionally not in an interference fit, and canoptionally rotate around the component 150. In an example, the polymercomponent 130 is overmolded on to the ring component 150.

In another example, after the polymer component 130 is disposed over therecess 154, tubing 133, for example low density polyethylene or heatshrink tubing, is disposed over the polymer component 130, and isshrunk, for example while heating, to deform the polymer component 130into the recess 154 of the ring component 150, as shown in FIG. 15. Itshould be noted that heat can be applied to the polymer component 130and/or tubing 133 for example, but not limited to, by a laser, such as aCO2 laser, RF, oven, inductive heater, YAG laser, diode laser, alone orin combination with added pressure. The ring component 150 is optionallyprovided with textured portions, or holes such that the polymercomponent 130 can be shrunk on to the textured portions or through theholes to mate with a second polymer component.

Referring again to FIGS. 12, at 214 and 216, elongate tubing 202 isdisposed over the polymer component 130, and the elongate tubing 202 issecured or coupled with the polymer component 130. Examples of theelongate tubing 202 include, but are not limited to, elastomericthermoplastic, such as 55D polyurethane. In an option, the elongatetubing 202 and the polymer component 130 have similar melting points.The elongate tubing 202 is coupled or secured with the polymer component130, as illustrated in FIG. 16. Example methods of securing or couplingat a joint include, but are not limited to, fusing with a laser, heatand/or pressure, or bonding with an adhesive.

FIGS. 17-19 illustrate additional options for the polymer component 130.The polymer component 130 includes a slitted portion 131 and/or anelement that allows for the polymer component 130 to temporarily expandfor installation, and contract to secure with the ring. The slittedportion 131 can have a variety of shapes, and extends in various waysradially and/or longitudinally. For example, the slitted portion 131 canextend substantially straight along a longitudinal portion, as shown inFIG. 17. Other examples includes FIGS. 18 and 19 shown a slitted portionextending in a helical shape, FIG. 18, or a stepped configuration, FIG.19.

The lead system is further assembled. For example, one or moreconductors are disposed within the elongate tubing, for example, bystringing. The one or more conductors are electrically coupled with oneor more electrodes, such as the distal electrode ring component.

Advantageously, the joint provided between the ring component, thepolymer component, and the elongate tubing can be made relativelyquickly, and will not degrade over time, even in a wet environment orwithin a body.

It is to be understood that the above description is intended to beillustrative, and not restrictive. It should be noted that the abovetext discusses and figure illustrate, among other things, implantableleads for use in cardiac situations; however, the present leads andmethods are not so limited. Many other embodiments and contexts, such asfor non-cardiac nerve and muscle situations or for external nerve andmuscle situations, will be apparent to those of skill in the art uponreviewing the above description. The scope should, therefore, bedetermined with reference to the appended claims, along with the fullscope of legal equivalents to which such claims are entitled.

What is claimed is:
 1. A lead assembly comprising: a lead body extendingfrom a proximal end portion to a distal end portion, the distal endportion comprising an interconnect including a polymer ring componentmechanically coupled to a generally cylindrical ring component having anouter surface, wherein a portion of an inner surface of the polymer ringcomponent is disposed over and in contact with the outer surface of thegenerally cylindrical ring component; at least one conductor extendingwithin the lead body from the proximal end in a direction toward thedistal end; and at least one electrode operatively coupled to the atleast one conductor.